Cam finishing apparatus



Dec. 14, 1965 l. G. WINER CAM FINISHING APPARATUS 2 Sheets--Sheei'l 1 Filed Nov. 21, 1963 @R Z N /MWM/ W W vl 5 M Dec. 14, 1965 l. G. WINER 3,222,822

CAM FINISHING APPARATUS Filed NOV. 21, 1965 2 Sheets-Sheet 2 United States Patent O 3,222,322 QAM FHNESHENG APPARATUS Irving G. Winer, 324i Kentucky Ave. S., St. Louis Park, Minn. Filed Nov. 2li, 1963, Ser. No. 325,284 8 Claims. (Cl. 51-144) This invention relates to apparatus for finishing cams and similar parts requiring smoothly finished edge surfaces. More particularly the invention is directed to apparatus for providing edge cams with a highly polished precision finish on their working edge faces.

The invention is illustrated in the accompanying drawings in which the same numerals are used to identify corresponding parts and in which:

FIGURE l is a perspective view of the cam finishing apparatus according to the present invention;

FiGURE 2 is a top plan view of the apparatus;

FGURE 3 is a fragmentary front elevation, partly in section taken on the line 3 3 of FIGURE 2 and in the direction of the arrows, of the finishing portion of the apparatus;

FIGURE 4 is a fragmentary and enlarged transverse section, on the line 4--4 of FIGURE 2 and in the direction of the arrows, showing one means for holding a cam to be finished in proper alignment; and

FIGURE 5 is a fragmentary view, in section, of an alternative means for causing reciprocating motion in the spindle supporting the cam to be finished.

Referring now to the drawings, the apparatus comprises generally a base iti supporting a frame or standard il which in turn supports a fiat horizontal top working platform 12. On one side of the apparatus there is mounted a motor i4 supported by a bracket 15 and having a driven shaft i6, to which is attached a drum 17. An endless belt i8 carrying a coating of fine abrasive material on its outer surface is driven by the motor through the shaft i6 and drum 1'7.

On the top platform l2 of the apparatus spaced back from the side mounting the motor 14 there is a bracket 19 which supports a rocker arm 2l for pivotal movement on a shaft 2t) carried in the bracket. At the opposite end of the rocker arm 21 from its axis of rotation about the pivot 2li there is journalled a spindle 22 for rotation relative to the rocker arm, and preferably for simultaneous reciprocating motion. Shaft `and spindle 22 are both preferably journalled in hardened steel bushings for minimum wear and maximum life.

Spindle 22 is rotated by virtue of attachment to the drive shaft of a second motor 23 mounted on a plate 27. The plate is provided with a slot 23 at one end which engages the shaft 2d so as to hold the motor against rotation relative to the rocker arm, so as to impart rotary motion to the spindle.

As described hereinafter, it is desirable that the spindle 22 reciprocate relative to the rocker arm 2i so as to distribute wear uniformly across the abrasive belt 18. One means of accomplishing such reciprocation is provided by a face cam 24 fixed to the spindle 22 for rotation therewith. A rotary cam follower 25 mounted on a shaft supported by a post or bracket 26 mounted on the top of the rocker arm 21 bears against the working face of the cam 24. A plurality of coil springs 30 extending between the plate 27 mounting the motor 23 and posts 29 extending on opposite sides of the rocker arm resiliently and uniformly urge the cam follower 25 against the face of the cam 24 at all times. As the spindle 22 rotates the cam 24 causes the motor 23 and the plate 27 supporting the motor to be urged closer to and farther away from the rocker arm causing reciprocal movement of the spindle relative to the rocker arm.

The cam 32 to be finished is supported at the free end 3,222,822 Patented Dec. 14, 1965 ice of the spindle 22 on the opposite side of the rocker arm 21 from the motor 23 and reciprocating cam 24. The cam 32 to be finished is secured to the spindle for rotation therewith along with a master cam 3l whose contours are desired to be exactly duplicated in the cam to be finished.

One means by which the master cam and cam to be finished may be mounted for rotation together is shown in FIGURES 3 and 4. A sleeve 33 of brass or other non-magnetic material is fitted with a plurality of longitudinally extending magnets 34 whose ends are coplanar with the ends of the sleeve 33. The cam 32 to be finished and the master cam 3l are butted up against the opposite ends of the sleeve 33 and held there by the attractive force of the magnets. The cams are located and positioned relative to one another by means of a timing pin 35 extending through the sleeve and projecting from the end faces of the sleeve to fit into a locating hole provided in each of the cams for purposes of alignment. The sleeve 33 is secured to the spindle by means of a set screw 36. It will be readily seen that both cams will rotate and reciprocate with the spindle and with each other simultaneously.

A pair of solid stable blocks extend upwardly from the top of the platform. The rst of these blocks 38 underlies the spindle and firmly and solidly supports a small diameter pin 37, preferably formed from wear resistant tool steel, spaced below and in approximate vertical alignment with the spindle. This pin 37 functions as a cam follower for the master cam 3i. The sleeve 33 and master cam 3l are so positioned on the spindle 22 that as the spindle rotates and reciprocates the edges of the master cani will at all times be in position to be in contact with the pin 37. The effect of this is that the master cam causes the rocker arm, along with the spindle and motor 23 and associated mechanism, to move on the rocker arm pivot up or down depending upon the particular contour of the master cam in contact with the follower pin at any instant.

The other projecting block 4l) is spaced from the first and firmly and solidly supports a second pin 39, desirably formed from wear resistant and heat resistant ceramic material, such as alumina or the like. The endless abrasive belt passes over this pin and the edges of the cam 32 to be finished move in contact with the abrasive belt as it passes around the pin and as the cam 32 rotates with the spindle. The pin 39 is in alignment with the master cam follower pin 37 but is of lesser radius by an amount equal to the thickness of the abrasive belt, in order to insure that the cam to be finished will have the exact dimensions as the master cam. Typically, pin 39 may be of the order of 1A inch diameter.

Depending upon the amount of material to be finished from the cam 32 in the finishing operation, the cam 32 to be finished may initially function as Vthe cam for controlling `movement of the rocker arm and associated mechanism until the edge contours of that cam have been reduced sufficiently to bring the master cam 31 into contact with .the cam follower pin 37.

The rocker arm is `desirably formed of relatively lightweight material. The weight of the rocker arm and the mechanism associated with it largely determines the pressure under which the cam to be finished is brought into contact with the abrasive belt. Within reasonable limits, the longer the rocker arm the more precise results maybe obtained. By means of the apparatus of the present invention cam edges have consistently been provided with finishes in the range from 2.1 to 2 micro-inch nish. The apparatus, according to the present invention, is not limited -to the finishing of convex cam contours but has successfully and consistently finished cams whose surfaces have concave as Well as convex contours.

In FIGURE 5 there is shown an alternative means for reciprocating the spindle. According to this embodiment of the invention the spindle is positively reciprocated :by means of reversible worm gear grooves 41 which are in contact with dog 42 when the spindle is rotated to cause positive reciprocation of the spindle and cams carried by it. The reciprocatory stroke is desiraibly about equal to the width of the abrasive belt. The earn supporting sleeve 33 is mounted on the spindle so that the cam to -be polished will traverse the width `of 'the belt in the ycourse of its reciproc-ation with the spindle.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specic embodiments described are given by way of example only and the invention is limited only by the terms of the appended claims.

I Claim:

1. Apparatus for finely finishing the surfaces of edge cams which comprises a stationary por-tion and a relatively movable portion; said stationary portion comprising support means for firmly and rigidly securing a master cam `follower pin and an axially aligned abrasive web support pin,

drive means for causing rapid movement of an endless web of abrasive material over said abrasive web support pin, and

mounting means for pivotally supporting one end of a rocker arm;

said relatively movable portion comprising a rocker arm pivotally supported in said stationary mounting means for limited movement,

a spindle journalled for rotation in said arm on an axis spaced generally horizontally from and parallel to the pivotal axis, and parallel to and spaced from and overlying the axis of the stationary pins,

drive means `for rotating said spindle relative to said arm, and

means adapted to secure a master cam and at least one cam to :be finished to said spindle for rotation there with, said securing means adapted to secure said master cam to said spindle overlying said cam fol' lower pin and said cam to be finished overlying said abrasive web support pin;

said relatively movable portions adapted to rotate said cams in edge contact with said stationary pins under force of gravity imposed by said movable portion, whereby the contours of said master cam are precisely reproduced in said cam to be finished.

2. Apparatus according to claim 1 further characterized in that said spindle is journalled for simultaneous reciprocal movement as it rotates.

3. Apparatus according to claim 2 further characterized in that said spindle is caused to reciprocate by virtue of face cam means secured for rotation with said spindle, cam follower means secured to said rocker arm and means for uniformly resiliently urging said cam follower into 'contact with the -face of said face cam.

4. Apparatus according to claim 2 further characterized in that said spindle is caused to reciprocate by virtue of reversing worm gear grooves in said spindle and an associated `stationary dog extending into said grooves and secured in said rocker arm.

5. Apparatus according to claim 1 further characterized in that the radius of said st-ationary cam follower pin is greater than the radius of the abrasive web supporting pin by the thickness of the abrasive web, whereby the master cam may have the same dimensions as the finished dimensions of the cam to be finished.

6. Apparatus according to claim 1 further characterized in that said drive means for said abrasive web comprises `an electric motor having a drum of substantially greater diameter than the diameter of the abrasive web supporting pin secured to its driven shaft, the axis of said driven shaft being parallel to and underlying the axis yof said pin and said drum being disposed below said pin.

7. Apparatus according to claim 1 further characterized in that said means for securing said master clam land cam to be finished to said spindle comprises a non-magnetic sleeve adapted to be attached to said spindle, a plurality of magnetic elements in the end surfaces of said sleeve to hold said cams by magnetic attraction and locating '".means to position said cams and prevent relative movement thereof.

8. Apparatus for imparting a precision finish to the surfaces of edge cams which comprises a stationary portion and a relatively movable portion;

said stationary portion comprising support means for firmly and rigidly securing a first master cam follower pin of relatively small diameter and a second pin of relatively small diameter adapted to support a moving web of abrasive material, said pins being wear and heat resistant and the radius of said first pin being greater than that of the second pin by the thickness of the web of abrasive material drive means for causing rapid movement of an endless web of abrasive material over said `second pin, said drive means including a relatively large diameter drum and motor means for rotating the same,

bracket mounting means for pivotally supporting one end `of a rocker arm; said relatively movable portion comprising a relatively .light and elongated rocker arm pivotally supported in said bracket for limited movement,

a spindle journalled for rotation and reciprocation in one end of said arm on an axis spaced `generally horizontally from and parallel to the pivotal axis of said bracket, and parallel to and spaced generally vertically above the axes of said stationary pins,

motor drive means for rotating said spindle relative to said arm, and

means adapted to be attached to said spindle overlying said pins to secure a master cam -and at least one cam to be finished to said spindle for rotation and reciprocation therewith, said securing means adapted to secure said master cam to said spindle overlying said first pin and said cam to be finished overlying the -abrasive web on said other pin;

said relatively movable portion being adapted to rotate `said cams in edge contact respectively with said first pin .and the abrasive web on said second pin under force of gravity imposed by the elements of said movable portion, whereby said master carn causes limited movement of the rocker arm corresponding to the contours of the master cam and said contours are precisely reproduced in said cam to tbe finished.

No references cited.

LESTER M. SWNGLE, Primary Examiner. 

1. APPARATUS FOR FINELY FINISHING THE SURFACES OF EDGE CAMS WHICH COMPRISES A STATIONARY PORTION AND A RELATIVELY MOVABLE PORTION; SAID STATIONARY PORTION COMPRISING SUPPORT MEANS FOR FIRMLY AND RIGIDLY SECURING A MASTER CAM FOLLOWER PIN AND AN AXIALLY ALIGNED ABRASIVE WEB SUPPORT PIN, DRIVE MEANS FOR CAUSING RAPID MOVEMENT OF AN ENDLESS WEB OF ABRASIVE MATERIAL OVER SAID ABRASIVE WEB SUPPORT PIN, AND MOUNTING MEANS FOR PIVOTALLY SUPPORTING ONE END OF A ROCKER ARM; SAID RELATIVELY MOVABLE PORTION COMPRISING A ROCKER ARM PIVOTALLY SUPPORTED IN SAID STATIONARY MOUNTING MEANS FOR LIMITED MOVEMENT, A SPINDLE JOURNALLED FOR ROTATION IN SAID ARM ON AN AXIS SPACED GENERALLY HORIZONTALLY FROM AND PARALLEL TO THE PIVOTAL AXIS, AND PARALLEL TO AND SPACED FROM AND OVERLYING THE AXIS OF THE STATIONARY PINS, DRIVE MEANS FOR ROTATING SAID SPINDLE RELATIVE TO SAID ARM, AND MEANS ADAPTED TO SECURE A MASTER CAM AND AT LEAST ONE CAM TO BE FINISHED TO SAID SPINDLE FOR ROTATION THEREWITH, SAID SECURING MEANS ADAPTED TO SECURE SAID MASTER CAM TO SAID SPINDLE OVERLYING SAID CAM FOL- 